People living in deprived areas face a lot of challenges in the UK. There is very little job security, many people being offered "zero hour" contracts so it's hard to predict your weekly or monthly income. If someone in such precarious situations see people from abroad being given housing, this can cause resentment. What is hard to understand is that EU citizens under the present system are not immigrants - they are migrants between "areas" of Europe. So the freedom of movement is a bit like someone from New York deciding to "migrate" or move to Miami for a job opportunity, or to be with family or simply because they prefer the weather....
There was also a lot of confusion concerning EU residents moving to the UK and people fleeing persecution crossing Europe on foot. So some people felt quite fearful of how much control the UK had over who moves in to the UK from outside its geographical borders....But in terms of EU freedom of movement, UK citizens are by far making the most use of this privilege: 4.9million Brits live in other parts of the EU.

You asked about budget: Each country puts in the pot according to GDP so the UK with the 4th largest economy [[pre referendum) would have put in an amount. The UK got an amount back from the EU ear-marked for deprived areas of the UK such as Cornwall and Wales, which the UK government was not able to cover by its own budget. [[The same areas voted to leave, on the basis that the Brexit campaign had promised that this EU funding would be matched by the UK government). What the Leave campaign also promised was more money for the UK health service. An hour after the referendum was announced, these promises were backtracked by a prominent Leave campaigned .... hmmmm......And then prominent leave politicians resigned one after the other...
So people are feeling a little confused, if not angry!

As for the better use of EU funds by our present politicians.....Let's just say I'd be pleasantly surprised if this actually happens! :-)